Orthostatic tremor (OT) is not an uncommon symptom in various neurodegenerative diseases. However, the nature and pathophysiology of OT involve a complex network of tremors and dopaminergic pathways. We assessed patients who complained of prominent leg tremors described as “shaky leg.” We analyzed their characteristics and evaluated them with neuroimaging and electrophysiological tools. A total of 23 patients who experienced an uncomfortable symptom of leg tremor were retrospectively enrolled from April 2014 to October 2019. Previous medical history, brain MRI, and surface electromyography (EMG) data were analyzed. The [18F]-FP-CIT brain positron emission tomography (PET) and the Unified Parkinson’s Disease Rating Scale (UPDRS) were assessed for patients who showed parkinsonism. The causes of OT varied: parkinsonism (n = 5), idiopathic causes (n = 4), secondary causes (n = 3, trauma, brain lesion, arteriovenous malformation), drug reactions (n = 3, valproate, perphenazine, haloperidol), other neurological disorders (n = 5, essential tremor, dystonia, restless leg syndrome, REM sleep behavior disorder, dementia), alcohol withdrawal (n = 1), functional movement disorder (n = 1), and an unknown cause (n = 1). The frequency range varied (2.6–15 Hz) and according to the new consensus statement on the classification of OT, 4 patients had primary OT, 2 had “primary OT plus,” 12 had slow OT, and 5 had orthostatic myoclonus. The prognosis associated with the use of medication was generally poor; however, clonazepam and levodopa were the most effective drugs. In conclusion, we found that different types of OT and orthostatic myoclonus were diagnosed by electrophysiological evaluation and neuroimaging tools even if they showed the same symptoms as “shaky leg.” In addition, it is possible to roughly estimate the response to medication according to the type of OT and the cause. To clarify the pathophysiology of OT, a large number of longitudinal cohort studies and detailed neuroimaging and electrophysiological evaluations are needed.

中文翻译：

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抖腿综合征患者该怎么办？23 名患者的回顾

直立性震颤 (OT) 在各种神经退行性疾病中并不少见。然而，OT 的性质和病理生理学涉及一个复杂的震颤网络和多巴胺能通路。我们评估了抱怨显着腿部震颤的患者，这些患者被描述为“腿部颤抖”。我们分析了它们的特征，并使用神经影像学和电生理学工具对其进行了评估。从 2014 年 4 月至 2019 年 10 月，共有 23 名经历过腿部震颤不适症状的患者被回顾性纳入，分析了既往病史、脑部 MRI 和表面肌电图 (EMG) 数据。[18F]-FP-CIT 脑正电子发射断层扫描 (PET) 和统一帕金森病评定量表 (UPDRS) 对表现出帕金森病的患者进行了评估。OT 的原因各不相同：帕金森综合征 (n = 5)、特发性原因（n = 4）、继发性原因（n = 3，外伤、脑损伤、动静脉畸形）、药物反应（n = 3、丙戊酸盐、奋乃静、氟哌啶醇）、其他神经系统疾病（n = 5、特发性震颤、肌张力障碍） 、不宁腿综合征、REM 睡眠行为障碍、痴呆）、酒精戒断（n = 1）、功能性运动障碍（n = 1）和原因不明（n = 1）。频率范围各不相同（2.6-15Hz），根据新的 OT 分类共识声明，4 名患者为原发性 OT，2 名患者为“原发性 OT 加”，12 名患者为慢速 OT，5 名患者为直立性肌阵挛。与使用药物相关的预后通常很差；然而，氯硝西泮和左旋多巴是最有效的药物。综上所述，我们发现不同类型的 OT 和直立性肌阵挛是通过电生理评估和神经影像学工具诊断出来的，即使它们表现出与“腿颤抖”相同的症状。此外，可以根据 OT 的类型和原因粗略估计对药物的反应。为了阐明 OT 的病理生理学，需要进行大量纵向队列研究和详细的神经影像学和电生理学评估。